There are still a number of people having issues with WIndows 10 Mail app and TPG email. These settings resolved the issues reported in this thread (Update password/Give permission to app etc etc). Do not setup the email account as IMAP4 - set it up as POP3.
Incoming & Outgoing mail server should be mail.tpg.com.au.
When you have setup the account go to "Settings-->Manage accounts" and select the TPG Account. Select
"Change mailbox sync settings".
Scroll down and make sure Synch options Email is set to "On".
Select Advanced mailbox settings.
Make sure that:
Incoming email server is set to --> mail.tpg.com.au:995:1
Outgoing (SMTP) email server is set to --> mail.tpg.com.au:465:1
Finally ensure all check boxes ticked for outgoing server requires authentication, same username password for sending mail, Require SSL incoming email and Require SSL for outgoing email
I could not get TPG to work with IMAP4 but will work with POP3.
These settings worked for both my default TPG email account and my slave TPG email account
